DIN 93 Tab Washers with Long Tab

DIN 93 tab washers with long tab are single-tab locking washers used to prevent rotational movement between a washer and the associated bolt, stud, or mating component. The standard identifies this product as a Tab Washer with Long Tab, while common market names include single tab washer, single tab lock washer, and locking safety washer. The washer has a central hole and a projecting tab that extends beyond the circular washer body.

The defining feature is the relationship between the flat washer body and the long tab. During assembly, the tab is positioned against an appropriate surface or feature of the joint so that the washer cannot rotate freely. This creates a mechanical locking function that differs from spring washers or toothed lock washers, which rely primarily on elastic action or surface engagement.

DIN 93 is particularly associated with metric fastener sizes and is available across a broad dimensional range. The published dimensional series covers sizes from M3 through larger metric diameters, with outer diameter, tab width, tab length, and washer thickness increasing according to the specified size.

The DIN 93 standard itself is withdrawn and has no direct replacement, but DIN 93 tab washers remain commercially available and are still identified by the DIN designation in the fastener market. Current suppliers continue to offer steel, A2 stainless steel, and A4 stainless steel versions using the DIN 93 dimensional designation.